Method of killing weeds



United States Patent 3,155,487 METHOD OF KILLING WEEDS Llewellyn W. Fancher, Lafayette, and Arthur M. Imel,

El Sobrante, Califl, assignors to Staufier Chemical Company, New York, N.Y., a corporation of Delaware N0 Drawing. Original application Nov. 24, 1959, Ser. No. 855,018. Divided and this application Jan. 16, 1962, Ser. No. 166,680

3 Claims. (Cl. 71--2.5)

This invention relates to 2,4-dialkoxy-6-mercaptoaryls-triazines. More particularly the invention relates to compounds of the following general formula:

wherein each R is an identical lower alkyl radical and X is an aromatic radical, substituted or unsubstituted.

The compounds of the present invention can be made in the following manner:

EXAMPLE 1 2,4-Dimethoxy-6- -Tolyl Mercapto-s-Triazine Seven and seven-tenths grams (0.062 M) of p-thiocresol was dissolved with warming in cubic centimeters of dioxane. To this solution was added with stirring 3.5 cubic centimeters (0.062 M) of 48 percent sodium hydroxide solution and the mixture cooled to 40 C. With rapid stirring, 10.5 grams (0.06 M) of 2,4-dimethoxy-o-chlorotriazine was added all at once. The temperature rose to 60 C. After the initial reaction had subsided, the mixture was heated on the steam-bath for one-half hour, then poured into cold water. The precipitated solid was filtered off, washed with water and air dried. By this procedure there was obtained 15.2 grams (97 percent of theory) of 2,4-dimethoxy-6-(ptolyl)mercapto-s-triazine. M.P. 85.5-86.5 C.

grams (0.05 M) of 2,4-diethoxy-6-chlorotriazine. yield was 11.8 grams (85 percent of theory).

phenols, additional members of this class of compounds were prepared:

The

R X m" or M.P.

Methyl- Phenyl 53-58 0. Do... m-Tolyl. 1. 5904 n-Propyl rln Do p-Tolyl 1. 5940 Do m-Tolyl 1. 5853 Do o-Tolyl 1. 5886 D Beta-naphthyl 1. 6432 n-Butyl henyl 1. 5199 D0 p-Tolyl 1. 5822 Do m-Tolyl 1. 5740 n-Octyl- Phenyl 1. 5285 The compounds of the present invention have been tested as herbicides and found very effective as the following typical tests show. Some of the compounds are quite selective in their action and can be used to eradicate or control one type of plant, while another type of plant is relatively unafiected.

In making the following tests, seeds were planted in 3 pots and shortly thereafter the compound under test was applied to the pots as a drench at the rate of 235 pounds per acre. The pots were placed in a greenhouse and watered at suitable intervals and the germination and growth of the seeds was compared with similarly planted seeds to which no herbicide was added. In each case, germination was reported on the scale of 0-100%, While growth was reported on a scale of 0-10, based on the seeds which germinated. Thus, 10010 indicates normal germination and normal growth.

The following data were obtained.

-D D l Analysls: PRE M RGI1NCE HERBICIDE TESTS Oats Cucumber Radish R X Percent Percent N S Ge; Gr; Ge Gr Ge Gr Estimated 15.9 12.1 100 3 0 0 Phenyl. Found-.. 15. 6 12. l 100 0 25 6 100 5 Do.

25 1 0 0 Meta tolyl. 75 4 50 3 25 2 Para tolyl. 100 5 0 0 Ortho tolyl.

EXAMPLE 2 2,4-Diethoxyfi-Plzenylmercapto-s-Triazine Using essentially the same procedure as in Example 1, except that the product being liquid was recovered by use of a solvent, 2,4-diethoxy-6-phenylmercapto-s-triazine was prepared from 6.6 grams (0.06 M) of thiophenol, 2.4 grams of sodium hydroxide dissolved in 5 cubic centimeters of water, 25 cubic centimeters of dioxane and 10.2

Ge -Germination. Gr;-Growth.

Further tests were made with 2,4 dimethoxy-6-orthotolyl mercapto-s-triazine and 2,4 dimethoxy-6-phenyl mercapto-3-triazine except that the rate of application was reduced to 10 lbs. per acre. Both of these compounds completely prevented the germination of redroot pigweed, Lambs-quarters, purslane and smartweed even at this low concentration.

3 This application is a divisional application of application S.N. 855,018, filed November 24, 1959, now abana cloned.

We claim: 1. The method of killing weeds comprising applying to soil the phytotoxic amount of wherein R is lower alkyl and X is selected from the group consisting of naphthyl, phenyl and tolyl.

2. The method of killing weeds comprising applying 4 to soil the phytotoxic amount of 2,4-dimethoxy-6-orthotolyl mercapto-s-triazine.

3. The method of killing weeds comprising applying to soil the phytotoxic amount of 2,4-dimethoxy-6-phenyl 5 mercapto-s-triazinc.

References Cited in the file of this patent UNITED STATES PATENTS 2,936,227 Gysin et a1. May 10, 1960 FOREIGN PATENTS 610,403 Canada Dec. 13, 1960 OTHER REFERENCES 15 Koopman: Nieuwe Herbicide 1,3,5-Triazine Derivaten, 1957, pages 27 to 30 and 58 to 62. 

1. THE METHOD OF KILLING WEEDS COMPRISING APPLYING TO SOIL THE PHYTOTOXIC AMOUNT OF 